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Airbox
Overview The Trophy airbox is a generic part that services both the 900 and 1200 via different cutouts and accepts adapters for both Mikuni and later Keihin carburetors The Trophy airbox is designed to not only house an air cleaner, but to also ensure that the air reaching the carburetors has the correct velocity at any given engine demand. Removing the airbox and replacing it with open element air cleaners will result in poor performance. Filters OEM Filters are sold with new airboxes. You cannot purchase only a filter from Triumph. The OEM filter can be washed and cleaned according to manufacturer's instructions. - as can non-OEM Non-OEM K&N and Pipercross sell a direct replacement air filter (not requiring replacement of the airbox) for both the 900 and 1200 bikes........Stories of performance changing (reducing) filters relate probably to cone type filters whose resonance cannot match that of the original tuned harmonics of the large airbox. But more importantly Cone types dont create enough vacuum to operate the fuel tap Modification To remove the airbox requires removal of all the rear bodywork and tank. Once the airbox rubbers are loosened, the airbox slides to the rear off of the carburetors. Once the carburetors are out, the airbox can slide towards the front of the bike and be removed. In order to reduce the effort in removing the airbox, Some enterprising souls developed the idea of cutting the rear half of the airbox vertically between the air horns. (most useful if the cut is to an extreme inside edge of either horn) This allows removal of one air horn separately, allowing the balance of the airbox to be removed from the opposite side or change of the filter in-situ. without disturbing the carburetors. Modified airboxes are much easier to install and remove. The narrow slice does not affect performance and there is no need to make good the cut. The essential check when remounting the airbox is that all the connections are airtight. The rubbers are orientation specific, and you may need to practice mounting them with the air filter removed. Be careful when re-mounting the modified airbox halves. Attach the top and bottom screws before mounting the longer side screws. This will reduce the risk of breaking the captive nut tabs on the inside of the airbox sides. A thin-shaft, long-handled Phillips or Japanese Machine Screw screwdriver is needed to attach the outer lower screws on the airbox when re-installing a modified airbox on the bike. The lower, middle screw may require a screwdriver bit and a spanner or box wrench. (cutting the airbox asymmetrically avoids the issue entirely as then all the screws are reachable) The use of brass inserts and zinc plated steel machine screws causes the later variety of airbox to seize.The photo shown shows a very central cut - this needs ideally to be over and hard up against the horn to make fewer screws required to remove the affected horn - the central screws are harder to reach and thus remain on the larger proportion. Rubber Bung Two rubber bungs position the airbox horns on the frame. When mounted, these bungs hold the rear half of the airbox rigidly and prevent any movement. (often lost and make no difference.)